Shielding device



Feb. 11, 1936. s-r E 2,030,275

SHIELDING DEVICE Filed March 12, 1935 1;! Van for:

.o! a hexagon having ports for the 1 'Pmud'r'sb. 11, use

PATENT OFFICE 4 smsmm PanlStrelnncLBer-Iin a corporation oi- Germany. to Siemens & Hale. Aktlengesdl- Application M 1:. ms. sa'u'us. 1am

In Germany March 10. 1984 llyinventionrelatestoashieldingdevice adapted for use in connection with spark plugs to prevent the radiation 01' electric waves. One oftheknowntypesotdevicesotthischaracter wasdesigncdinsuchamannerthatitslower partwastastenedtothemotorupontightening thesparkpluginplacethispartbeingprovided at the upper end with a screw joint or the like arranged to complete the structure. In another know arrangement, a member carrying a locking springissecm'edtothespark plug,pressinginto place a shielded cable socket oi. suitable dedgn.

These structures consist at least 01' two separate members which are led upon applying themtothesparkplug. Thevariouspartsofthe device must be individually dismantled and assembled, respectively. upon removal or attachment oi the corresponding spark plug.

Another known type of shield may be fitted as a whole over the spark plug and removed from the same. It consists of two cylindrical metal sleeves fitted into each other, by means of which thedevicemaybesecuredtotheoi'the gland nut oi' the spark plug. The device comprises among other structural parts various e:- pensive metal members which are under the action of a strong spring; moreover, the diameter of thisstructure is larger thanthe outerdiameter oi the hexagonal portion of the spark plug. aecordingLY. where crowded conditions prevail it can notbeplacedoverthesparkplugatalloronly with difiiculties. 4

The object of my invention is to eliminate the above noted drawbacks and is accomplished y employing a shielding device com 01 two metal sleeves fitted into each other, the outer sleevehaving a diameter smallerthan theouter diameter of the hexagonal portion 0! the spark plum and carrying at the upper end a screw Joint, the lower end thereoi being designed in the o corner of the hexagonil portion oi! the plug body. Consequently, the sleeve may be placed over the spark plug from above and secured to the hexagonal portion oi the spark plug after a partial rotation by-means of the inner sleeve andot the screwjoint.

In the accomp y drawing which shows an embodiment 01' my invention in diagrammatic form, and in which similar reference characters I away portion of the sleeve.

14 cum. (0!. ice-m) Itisfittedvinametalsieevelhaving portslattheiowerendwithwebsllyingtherebetween. Thelowerendoithemetalsleeveiis end otthe sleeve 2 provided with a poi-hon for the screw joint or cl I. Insidethemetalsleevelisplaceda cap I of suitable insulating material (e. g..

Theassemblyoftheshielding deviceisefiected inadveltenttoi'thescrewiointlmay be prevented in any suitable manner.

The shielding device ispassed over thespark itrestsonthehexagonalportionoithespark Even when securing the shield to the spark plug v and from any desired angle.

which might be 11 may be brought about plug. Upon further screwing in the joint I into themetalsleevelthelatteriscausedtomove in the upward direction until the lower edge thereof firmly contacts with the lower surface oi the hexagonal portion of the sparkplug. vThe device is thus firmly clamped on the hexagon of the spark plug. An undesirable rotation-oi the shielding device in the one direction is prevented by teeth ll arrangedattheloweredge otthe metal sleeve 2 which engage the surface of the hexagonal portion of the spark plug, whereas a rotation in the other direction is prevented by the-webs l which are somewhat twisted and which also contact with the surfaces of the hexagonal portion of'the spark plug. Instead of theteeth ll inclined surfaces may be employed.

The shielding device has the advantage that it need only be moved in the axial direction when beingplacedoverorremovedi'romthespark plug. Furthermore, since its diameter is smaller than the outer diameter or the hexagonal portion of the spark plug. the cap like device may be easily placed over the spark plug even in the case or very crowded conditions. The device consists substantially of simple, light and economical parts, particularly of thin-walled tubes, the manufacture or! which requires no P t cular methods, and can bevmanipulated easily and piacedover or removed from the spark plug w th one hand. Ii' the screw joint I is loosened, the

entire arrangement can be rotatedacertain extent and placed in position for-easy removal.

rotate slightlyuntil the clamping and locking on thehexagonisaccomplished.

Due to the design of the lower portion of the metal sleeve 2 in the form 01' a hexagon the device may be placed over the spark plug in six diilerent positions so that it is possible to introduce the cable into the shielding device easily Slight changes by rotating the bushing member ll within the opening l2 of the metal sleeve 2. x

In order to prevent a loosening of the screw joint 5 a locking device It may be provided, com- -prisingaspringsecuredtothebodyoftheouter sleeve 2 whichis adapted to engage any oi the notches on the peripherally knurled closure 5 as Inordertoensure cooling ofthesparkplugsin spite oi the shield the metal sleeve I may be provided at the lower end thereof with suitably screened ports. The shielding etl'ect is thereby not impaired, since'the heat may be disipated through the screening (wire nettings and the like) and through the ports I into the metal sleeve 2.

cylindrical metal sleeve the diameter of which is less than the edgewise diameter 01 the hexagon oisaidsparkplugmneendorsaidsleeveiorming a hexagon arranged i'orplacing said sleeve overthe hexagon or said spark plug, ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, an inner sleeve disposed in said outer plugs having a hexagon comprising, an outer cylindrical metal sleeve the diameter of which is less than the edgewise diameter 01 the hexagon oi said spark plug, one end of said sleeve forming a hexagon arranged for placing said sleeve over the hexagon of said spark plug, ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, an inner sleevedisposed in said outer-sleeve, a screw Joint at the other end of said outer sleeve for axially securing said device tor-said spark plug hexagon by means of said inner sleeve, and means on said outer sleeve for locking said device. against rotation.

3. A shielding device for attachment to spark plugs having a hexagon comprising, an outer cylindrical metal sleeve the diameter of which is less than the edgewise diameter of the hexagon oi. said spark plug, one end of said sleeve forming a hexagon arranged for placing said sleeve over the hexagon oiv said spark plug. ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, webs between-said ports, said webs being twisted to secure rotation of said sleeve on said spark plug hexagon oi about 30, an inher sleeve disposed in said outer sleeve, and a screw joint at the other end of said outer sleeve for clamping said device onto said spark plug hexagon by means oi'said inner sleeve.

4. A shielding device for attachment to spark plugs having a hexagon comprising, an outer cylindrical metal sleeve the diameter of which is less than the edgewise diameter of the hexagon of said spark plug, one end of said sleeve i'orming a hexagon arranged for placing said sleeve over the hexagon of said spark plug, ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, ribs between said ports, the material of said sleeve at said end thereof being pressed inwardly intermediate 01' said ribs, an inner sleeve disposed within said outer sleeve, said inner sleeve being held in place in one direction by said inwardly pressed material of said end 01' the outer sleeve, and a screw joint at the other endoi said outer sleeve for clamping said -device onto said spark plug hexagon by means of said inner sleeve.-

5. A shielding device for attachment to spark plugs having a hexagon comprising, an outer cylindrical metal sleeve the diameter of which is less than the'edgewise diameter otthe hexagon of said spark plug, one endo! said sleeve forming a hexagon arranged for placing said sleeve over the hexagon of said spark plug, ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, an inner sleeve disposed in said i outer sleeve, a screw joint at the other end of said outer sleeve for clamping said device onto said spark plug hexagon by means 01' said inner sleeve, and means for locking said screw joint.

6. A shielding device for attachment to spark l plugs having a hexagon comprising, an outer cylindrical metal sleeve the diameter of which is lessthantheedgewisediameterofthehexagon of said spark plug, one end of said sleeve forming a hexagon arranged for placing said sleeve over the hexagon of said spark plug, ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, an inner sleeve disposed in J said outer sleeve, a screw Joint at the other end of said outer sleeve for clamping said device onto said spark plug hexagon by means of said inner sleeve, an insulating cap disposed within said inner sleeve, a lateral duct in said cap for receiving the end of an electric conductor, and terminal means within said duct at the inner end thereof for establishing connection between said cable and the central electrode of said spark plug. 7. A shielding device for attachment to spark a plugs having a hexagon comprising, an outer cylindrical metal sleeve the diameter of which is I less than the edgewise diameter of the hexagon of said spark plug, one end of said sleeve forming a hexagon arranged for placing said sleeve over 5 the hexagon of said spark plug, ports in said hexagon on said sleeve for receiving the edges of said spark plug hexagon upon rotating said sleeve thereon, an inner sleeve disposed in said outer sleeve. a screw Joint at the other end of I said outer sleeve for clamping said device onto said spark plug hexagon by means of said inner sleeve,aninsulatingcapdisposedwlthinsaid inner sleeve, a lateral duct in said cap for receiving the end of an electric conductor, terminal means within said dust at the inner end thereof for establishing connection between said cable and the central electrode of said spark plug, one end of said terminal means forming a hollow rivet arranged to expand by axial displacement, a and conductor means for connecting said end of the terminal means withthe central electrode of said spark plug. J

8. In combination with -a spark plug having a hexagon, a shielding device for attachment to the hexagonal portion thereof, said device comprising, a tubular sleeve one end of which is arranged to be slipped over said hexagonal portion and ports in said end ofsaid slee e arranged for rotating said sleeve relative to said hexagonal portion whereby the edges thereof enter into said ports, a tubular companion sleeve within said first sleeve, and closure means at the other end of said first sleeve arranged to actuate the second sleeve for locking said hexagonal por- 5 tion within said ports of said first sleeve.

9- In combination with a spark plug having a hexagon, a shielding device for attachment to the hexagonal portion thereof, said device comprising, a tubular sleeve one. end of which is arranged to he slipped over said hexagonal portion, and ports in said end of said sleeve arranged for rotating said sleeve relative to said hexagonal portion whereby the edges thereof enter into said ports. a tubular companion sleeve disposed within said firstsieeve, closure means at the other end of said first sleeve arranged to actuate saidsecnd sleeve for axially locking said shielding device on said hexagonal portion by means of said ports in said first sleeve, and means on said first sleeve for securing said device against radial displacement. 7

10. In combination with a spark plug having a hexagon, a. shielding device for attachment to the hexagonal portion thereof, said device comprising, a tubular sleeve one end of which is arranged to he slipped over said hexagonal portion and ports in said end of sleeve arranged for rotating said sleeve relative to said hexagonal portion whereby the edges thereof enter into said ports, a tubular companion sleeve disposed within said first sleeve, closure means at the other end of said first sleeve arranged to actuate said second sleeve for axially locking said shielding device on said hexagonal portion by means of said ports in said first sleeve, means in said first sleeve for securing said device on said spark plug against radial displacement, an insulating member within said device and a lateral duct therein for receiving an electrical conductor, terminal means on said duct for connection with said conductor, and means for connecting said terminal means with theelectrode'of said spark plug.

11. A shielding device for attachment to a spark plug having a wrench receiving portion comprising, in combination, an outer shell member, alternate projections and recesses at one end of said shield member for direct engagement with said wrench receiving portion of said plug, an

inner tubular member disposed movably within said shell outer member, and means at the other I end of said shell member for moving said inner member relative to said outer member to secure the attachment of said device on said spark plug with said projections and recesses of said shell member surrounding said wrench receiving portion thereof.v

12. The structure defined in claim 11, particularly for a spark plug having a hexagon, wherein the end of said outer shell member having said alternate projections and recesses is arranged. to

he slipped over said hexagon, whereby said outer shell member may be rotated relative to said hexagon to enter the edges of said hexagon in said recesses. v

13. The structure defined in claim 11, together with a unitary insulating member disposed within said inner tubular member, and terminal means in said insulating member connected to the electrode of said spark plug. Q

14. The structure defined in claim 11, together with a unitary insulating memberdisposed within said inner tubular member, terminal means in said insulating member, means connecting said terminal means with the electrode of said spark plug, and a duct in said insulating member for receiving the end of a cable to be connected to said terminal means.

PAUL STREHMEL. 

